Flame retardant polyester resinous composition containing halogen and phosphorus



United States Patent Divided and this application Sept. 21, B59, tier.No.

14 Claims. (Cl. 161-491) This invention relates to new resinouscompositions, comprising a polymerizable mixture of an unsaturatedpolyester (also referred to in the art as an unsaturated alkyd, or,unsaturated linear polyester resins) and an unsaturated cross-linkingagent, said mixture including a chemically combined component whichimparts flame retardance to the polymerized mixture which is a chemicalreaction adduct of a hexahalocyclopentadiene with an unsaturatedpolycarboxylic acid or acid anhydride or acid halide or an unsaturatedpolyhydric alcohol or esters thereof, and said mixture also including aphosphorus containing compound which compound is reactive in theesterification reaction so that the phosphorus becomes chemicallycombined in the polyester. This invention also relates to thepolymerized, flame retardant compositions in their finally reacted form,that is, as resinous, insoluble, infusible compositions, in whichphosphorus is chemically combined prior to the cross-linking reactioneither in the unsaturated polyester or in the unsaturated cross-linkingagent.

This is a division of the parent application Serial No. 635,949, filedlanuary 24, 1957, now Patent No. 2,931,746.

This application is a continuation-in-part of our c0- pendingapplication Serial Number 388,921, riled September 10, 1952, now UnitedStates Patent 2,779,701, and more particularly relates to halogencontaining polyesters of the type described therein, also containingcombined phosphorus in the finally reacted resinous composition, whereinthe phosphorus is derived either from the polyester portion of the resinor the cross-linker portion of the resin or both.

The production of infusible, insoluble polyester resins which areretardant and have high resistance to heat is of considerable commercialimportance. For instance, castings, moldings, foamed articles orlaminated structures bonded by polyester type resins are, for many uses,required, or at least desired, to be resistant to fire and are alsorequired to endure heat Without deterioration. A typical illustration ofan application having such a requirement is found in castings for liveelectrical contacts, which must not be ignited by sparks nordeteriorated by heat generated therein. Structural members, pipes, wallcoverings, panels, ash trays, etc., are f rther illustrations whereflame retardance is desirable.

Heretol'ore certain chemical adducts have been disclosed as being usefulin the preparation of polyester resins. For example, it is known thatthe maleic acidcyclopentadiene Diels-Alder adduct resulting from thediene synthesis and its reaction products with alpha, betaunsaturateddicarboxylic acids or anhydrides and glycols form resinous compositionswhich may be made insoluble 3,l3l,ll5 Patented Apr. 28, 1954 andinfusible by further reaction with copolymerizable olefins to form across-linked polymer. Such compositions are chemically different fromthe products of this invention because the double bond remaining in thelinear unsaturated polyester so produced is highly reactive and canenter directly into the cross-linking reaction, whereas, thecorresponding linkage in the halogen-containing derivatives employed inmaking the compositions of this invention is non-reactive in saidcopolymerization reaction. Moreover, they do not possess flameretardance. Attempts have been made to impart flame retardance to suchhydrocarbon type resinous polyester compositions by incorporatingtherein inert fireproofing agents, such as antimony oxide or chlorinatedparaffin wax, as fillers which do not enter into chemical reaction withthe components of the resin; however, this results in a loss in thedesirable properties, particularly with respect to heat resistance,which are usually associated with polyester resins; likewise theproperty of being able to produce satisfactory articles of commerce maybe seriously impaired. Furthermore, the mere addition of phosphoruscompounds such as triphenyl phosphate, tricresyl phosphate, triethylphosphate, trixylyl phosphate etc. as additives in physical combinationare equally unsatisfactory. Other attempts to impart flame retardanceare also known which involve chemically combining tetrachlorophthalicacid or anhydride in the polyester resin. Compositions so produced arechemically unrelated to the products of this invention; they have onlypoor flame retardant properties and they usually possess low stabilityand low strength at elevated temperatures; therefore, they are notentirely satisfactory for many applications. Still other attemptsinvolving the use of certain unsaturated organic phosphorous compoundsas cross-linking agents which impart flame retardance to the finalpolyester resin have likewise been found unsatisfactory.

It is an object of this invention to provide resinous compositions whichare highly resistant to burning and yet possess many of the desirablecharacteristics usually associated with polyester resins. A furtherobject is to provide resinous compositions which are highly resistant toexposure at elevated temperatures. A still further object is to prepareresinous compositions which are suitabl for casting, molding, foaming orlaminating and which are characterized by possessing the desirableproperties usually required in resins in the preparation of castings,moldings, foamed articles and laminates, and which are alsocharacterized by being capable of forming ar ticles of commerce whichhave a pleasing appearance and wide utility. A particular object of thisinvention is to make available in commerce compositions comprising amixture of an unsaturated polyester and an olefinic crosslinking agent,with or without the presence of catalysts and/ or inhibitors and/ orpromoters or accelerators, which are capable of polymerization to aninsoluble, infusible, fire resistant polyester resin. A furtherobjective is to provide methods for chemically combininghexahalocyclopentadienes in the form of an adduct into the polyester. Astill further objective is to provide methods for the preparation ofthese unsaturated polyesters and their combination with olefiniccross-linking agents.

The principal objective of this invention is to incorporate phosphoruschemically into a component of the polymerizable mixture of theaforementioned unsaturated polyesters, or by means of the olefiniccross-linking agent so that the final copolymer contains phosphorus inchemi cal combination, thereby obtaining a final copolymer whichpossesses greatly improved resistance to fire over such resins withoutphosphorous, improved resistance to weathering over such non-containingphosphorus resins, and also possessing good color characteristics amongother advantages.

These objects, and still others which will become apparent to thoseskilled in the art on consideration of our specification and claims, areaccomplished by the present invention.

In accordance with this invention the unsaturated polyester may containthe component which imparts flame retardance in either thepolycarboxylic acid or anhydride unit and/or in the polyhydric alcoholunit of the polyester. The unsaturated polyester must containunsaturation which is capable of copolymerization with the unsaturationin the cross-linking agent. Such copolymerizable unsaturation is anessential characteristic of the unsaturated polyester portion of themixture of this invention. We have found that the double bond, remainingin a polyester chain, which is derived from the reaction adducts ofhexahalocyclopentadienes with monooleflnic polycarboxylic acids oranhydrides, or mono-olefinic polyhydric alcohols or, esters thereofincluding acid chlorides is not sufliciently reactive to enter into thecross-linking reaction. We render such polyesters copolymerizable in thecrosslinking reaction by incorporating in the esterification product areactive and unsaturated chemical ingredient which retains its activeunsaturation after being chemically combined in the polyester chain.Alternatively, or in addition to including flame retardant components inthe unsaturated polyester, as just described, and in accordance withthis invention, the cross-linking agent may contain the component whichimparts flame retardance to the polyester resins of this invention.

The reactant components which impart flame retardance to the finalpolymerized resinous compositions included in this invention, i.e., thepolyester resins, may best be prepared by effecting the chemicaladdition of a hexahalocyclopentadiene with an unsaturated polycarboxylicacid or acid anhydride or acid halide, or an unsaturated polyhydricalcohol, or esters thereof, presumably in accordance with the followingequations, respectively, in which the specific reactants are given forpurposes of illustration only:

These, and similar Diels-Alder type reaction adducts ofhexahalocyclopentadienes which are more fully disclosed hereinafter, canbe csterified with a polyhydric alcohol or a polycarboxylic acid, toproduce a soluble polyester chain containing the olefinic linkageoriginally present in the Diels-Alder adduct, as exemplified by thefollow- 4 ing product formed by esterification of the product ofreaction (I) with ethylene glycol:

, esterifying the foregoing components in the presence of a reactiveunsaturated chemical ingredient which is capable of rendering thepolyester copolymerizable even after it is in chemical combination inthe polyester molecule. A particularly suitable material for this use ismaleic anhydride; however any unsaturated polycarboxylic acid oranhydride, or, polyhydric alcohol, or, esters thereof, including theacid chlorides, capable of esterification without losing its ability tocopolymerize with olefmic cross-linking agents may be employed.Alternatively, or in addition to providing unsaturation in this manner,we may also provide for it by employing a Diels-Alder reactant withhexahalocyclopentadiene which has more than mono-olefinic unsaturation,for example a di-olefin or an acetylenic compound, and which retains,after being esterilied in the polymter chain, an unsaturated linkagereactive in the cross-linking reaction.

While so esterifying the foregoing material of the nature of Formula illwith a material capable of rendering it copolymerizable, we mayintroduce a phosphorus containing material into the esterificationmedium so as to chemically incorporate phosphorus into the polymerizablemixture. However, if desired, the phosphorus can be introduced later bymeans of the cross-linking agent when copolymerizing. In either case wehave found that even though the aforedescribed copolymerized resinousmaterials have excellent flame resistance without any chemicallycombined phosphorus contained therein, yet even greater fire resistancecan be achieved when phosphorus is incorporated in accordance with thisinvention.

In addition we have found that compositions of this invention which haveonly moderate flame resistance, because of a lowered halogen content,have excellent flame resistance when chemically combined phosphorus isincluded in the composition. Although the halogen content of the finalcopolymerized resins in the examples following is shown to beapproximately between 21 and 29 percent, halogen percentages as low as 7percent may be used by taking advantage of the fire resistant propertieslent to the composition by the chemically combined phosphorus whilestill maintaining the good flame resistance of these resins. The upperlimit of halogen content is dictated by the molar limit of halogenatedintermediate that can be used in the polyester while still maintainingcopolymerizable unsaturation in the polyester chain. This upper limit isin the neighborhood of 57 percent if the cross-linking agent is of theunhalogenated type and 59 percent when both the polyester andcrosslinlzing agent are halogenated.

If the halogen content of the polyesters is lowered, increasing amountsof phosphorus are added in order to maintain good flame-resistancecharacteristics of the final polymerized resin. Relatively smallpercentages of phosphorus, based on the final copolymerized resin, areall that are required in order to preserve good flame resistance. Thesepercentages normally will vary between approximately 0.1 percent and 2.5percent although compositions employing as low as 0.05 percent aresuificient to show some improved flame resistance and quantities ofphosphorus as high as approximately percent may sometimes be fullychemically incorporated depending upon the types of polyester,cross-linking agent and phosphorus introducing chemical employed.

Among the phosphorus containing materials which may be used in order tochemical y combine the phosphorus in the copolymerized resin byintroducing the phosphorus as a part of the polyester portion of theresins of this invention are: phosphorus oxychloride, phosphoruspentachloride, hydroxymethyl phosphonic acid, phosphorous acid,phosphorus trichloride, phosphoric acid, benzene phosphonic acid, trismethylol phosphine oxide, bis-hydroxymethyl phosphinic acid and thelike. Certain of these phosphorus containing materials becomeincorporated in the acid portion of the polyester while others becomeincorporated in the alcohol portion of the polyester while hydroxymethylphosphonic acid links up with both portions of the polyesters.

Among the phosphorus containing materials which may be used in order tochemically combine the phosphorus in the copolymerized resin byintroducing it as a part of the monomeric cross-linker are diallylbenzene phos phonate, bis (betachloroethyl) vinyl phosphonate, di-(chloropropyl) propenyl phosphonate, tri-allyl phosphate, di-allyl ethylphosphate, allyl diethyl phosphate, allyl propyl phosphate, allyldipropyl phosphate and the like.

The resinous compositions of this invention can be prepared by firsteffecting the esterification of the selected polycarboxylic acids withthe desired polyhydric alcohols in the presence of one of the phosphoruscontaining materials listed in the next preceding paragraph and in thepresence of the reactive unsaturated chemical ingredient, whereby anunsaturated polyester is formed; then mixing the resulting compositionwith the chosen copolymerizable olefinic cross-linking agent; and,thereafter copolymerizing the mixture to form an insoluble, infusiblepolyester resin. Another method which may be employed for producingresinous compositions of this invention, which is in accordance with ourfindings, comprises effecting the chemical addition ofhexahalocyclopentadiene to less than the total theoretical number or"olefinic linkages contained in an unsaturated polyester molecule in thepresence of one of such phosphorus containing materials listed above.For example, by effecting the Diels-Alder reaction of one molecule ofhexahalocyclopentadiene with one molecule of polyethylene glycolmaleate, a product is produced which contains thehexahalocyclopentadiene in chemical combination in the polyester chainand which also contains active unsaturation which is copolymerizable inthe cross-linking reaction; the product so produced is then combinedwith the chosen olefinic crosslinking agent and thereaftercopolymerized. Esteriiication of the desired ingredients may be eflectedin the presence or" esterification catalysts and/or chain terminatingagents, etc. A preferred procedure involves introducing the selectedingredients to be esterified, and the phosphorus containing material inpredetermined proportions, into a suitable esterification vesselprovided with heat ng and/or cooling means, an agitator, means forpassing an inert as such as nitrogen or carbon dioxide through thereaction mixture, means for removing water or" esterification, an inlet,an outlet, and any other accessories necessary for the reaction. Thecharged reactants are blanketed with an inert atmosphere, then agitatedand heated to effect the reaction for the specified period of time.After the desired degree of reaction has been attained, as convenientlydetermined by employing the acid number technique or measuring theamount of water liberated, the reaction mixture is cooled. The resultingproduct, if solid, and if prepared in accordance with the firstprocedure described, is broken up and then mixed with the olefiniccross-linking agent at room temperature, preferably in the presence of apolymerization inhibitor. If prepared in accordance with the secondmethod, a hexahalocyclopentadiene is chemically added to a solubleunsaturated polyester molecule in an amount insuiiicient to react outall the double bonds in the polyester and the material resulting by thistreatment is then compounded with the olefinic cross-linking agent.

We have found that the cross-linking agent may be advantageouslycombined with unsaturated polyesters prepared in accordance with thesemethods while the unsaturated polyester is at an elevated temperatureand that the olefinic cross-linking agent may also be at an elevatedtemperature thereby facilitating solution and mixing. To preventpremature polymerization at this stage, a polymerization inhibitor isadvantageously added to the mixture, or, preferably to one of itscomponents prior to mixing, especially if the mixture is to be stored orshipped in commerce prior to curing or effecting the copolymerizationreaction into the insoluble, infusible, polyester resin. Alternatively,or in addition to including a polymerization inhibitor, a catalyst and/or promoter for the copolymerization may be added, particularly if it isdesired to make available in commerce a composition which is ready forpolymerization and does not require further chemical additions in orderto be used, as is commonly known in the art.

In order that this invention may be more readily understood and tofurther illustrate the details thereof, the following examples are givenwhich show preferred compositions of this invention and methods fortheir preparation. Certain of the Diels-Alder adducts ofhexahalocyclopentadiene disclosed herein are new compositions of matterwhich are more fully described, including methods for their preparation,and claimed in the copending applications hereinafter identified.

In the following examples, in which parts are given by Weight unlessotherwise stated, flame retmdance is reported as burning rate in inchesper minute determined by ASTM D757-49, the specifications for this testbeing: A glow bar is heated to 950 degrees centigrade by alternating ordirect current, the electrical input of which is adjusted to 358i20watts. A test specimen 5 x /2 x /8 inches is clamped in a holder withits length horizontal and at right angles to the axis of the ignitingbar and its width in a vertical plane. The length of the specimen freeto burn is four inches. The front end of the specimen is brought intocontact with the igniting bar and allowed to remain in this position forthree minutes. After three minutes any flaming shall be extinguished,the specimen removed, and the length burned measured. The length burneddivided by three then gave the burning rate in inches per minute.

Heat distortion temperature, defined as that temperature in degreesCentigrade a plastic specimen, A5 to M2 inches by /2 inch by five inchesand supported on its narrowest side by metal supports four inches apartand immersed in a suitable liquid heat transfer medium, which is raisedin temperature at a rate of 2 degrees per minute, and under a fiberstress load of 264 pounds per square inch at the center, deflects at thecenter a distance of 10 mils or 0.01 inch. This test is carried outaccording to ASTM specification D-648-45T titled Heat DistortionTemperature of Plastics.

Color Hazen determined on the liquid polyester resin compound prior tobein copolyrnerized, is reported as units of color produced by platinum,in the form of the ehloro-platinate ion per liter of water. Each unit ofcolor is that produced by one milligram of platinum, in the form of thechloro-platinate ion, per liter. A color Hazen of 200 would therefore beequivalent to that produced by 200 milligrams of platinum per liter.This method of preparing color is taken from paragraph 3.2, page 88 ofStandard Methods for the Examination of Water, Sewage and IndustrialWastes, Tenth Edition, 1955, prepared and published by the AmericanHealth Association, Inc.

7 EXAMPLE 1 Fifty-two and eight-tenths parts of ethylene glycol and 90parts of diethylene glycol were charged into an esterification or resinvessel provided with heating and/ or cooling means, an agitator, meansfor maintaining an atmosphere of an inert gas over the reaction mixture,means for removing water of esterification, temperature recording means,charging inlets and outlets, etc. The charge was blanketed with an inertatmosphere of nitrogen, agitated, heated to a temperature between about80 to 100 degrees centigrade, then 394.7 parts of 1,4,5,6,7,7-hexachlorobicyclo-(2.2.1 )--heptene-2,B-dicarboxylic anhydride(hereinafter referred to as HET), prepared by the method which involvesthe Diels-Alder reaction of hexachlorocyclopentadiene with maleicanhydride, Was blended into the agitated glycols. Seventy andeighttenths parts of maleic anhydride was then blended into the chargedreactants while the reaction mixture was being raised to a temperatureof about 160 to 170 degrees centigrade by application of external heat.The water of esterification liberated during the reaction was separatedand periodically measured and the acid number of the reaction mixturewas also periodically measured to determine the progress of thereaction. When an acid number of approximately 55 was approached, 3.6parts of tetrahydrofurfuryl alcohol was added to the reaction mixture.Upon reaching an acid number of about 45 the entire contents of thereaction vessel was cooled, then cast into pans under an inertatmosphere. A transparent, faintly colored, hard, brittle, solublematerial, having 38.4 percent by weight chlorine content, melting in atemperature range above room temperature and below 100 degreescentigrade, and having a specific gravity at room temperature of about1.45 was obtained.

EXAMPLE 2 One hundred grams of the cast product recovered in Example 1was broken into small lumps, then added in small portions, withagitation, to 30 grams of styrene maintained under an inert atmosphere,containing 0.03 gram of hydroquinone, until completely dissolved.Complete solution consumed a period of more than 24 hours even withcontinued vigorous agitation. The resulting mixture was a clear,substantially colorless solution having a viscosity of about 30 poisesat 25 degrees centigrade on a Gardner bubble viscometer.

EXAMPLE 3 Fifty parts of the mixture prepared in Example 2 were agitatedwith 0.5 part of a catalyst mixture comprising 50 parts of benzoylperoxide and 50 parts of tricresyl phosphate. The resulting mixture wascast in a glass tube 16 inches long and having an inside diameter of 1 7inches and set by heating at a temperature of about 80 degreesCentigrade for a period of about one-half hour. A hard, tough, clear,insoluble, infusible substantially colorless polyester resin wasobtained which has a 30 percent chlorine content by weight and which wasimmediately self-extinguishing on removal from an oxidizing flame,giving a result of 0.18 inch per minute by the ASTM D75749 test, a colorHazen of 120, and a heat distortion temperature of 82 degreescentigrade.

The data for making the polyester and cross-linked resin of Examples 1,2, 3, are reproduced from our parent and copending application, SerialNo. 308,921, filed September 10, 1952, of which this application is acontinuation-in-part. Examples 4 and 5 following are based on Example 22of said copending application.

EXAMPLE 4 One hundred grams of the cast product recovered in Example 1were broken into small lumps, then added in small portions, withagitation, to 30 grams of diallyl benzene phosphonate, until completelydissolved. The resulting mixture was very viscous.

EXAMPLE 5 Fifty parts of the mixture prepared in Example 4 were agitatedwith 0.5 part of a catalyst mixture comprising 50 parts of benzoylperoxide and 50 parts of tricresyl phosphate. The resulting mixture wascast in a 16 inch by 1 inch inside diameter glass tube and set byheating at a temperature of about degrees centigrade for a period ofabout one-half hour. A hard, clear, insoluble, infusible, substantiallycolorless polyester resin was obtained which had a 30 percent chlorinecontent by weight and which was immediately self-extinguishing onremoval from an oxidizing flame, and gave an ASTM D757-49 result of 0.12inch per minute, a color Hazen of and a heat distortion temperature of82 degrees centigrade.

The following example illustrates the employment of l,4,5,6,7,7hexachlorobicyclo (2.2.1)-5-heptene-2,3-dicarboxylic acid (hereinafterreferred to as HET acid) in place of the anhydride as given in Example 1and is re peated from Example 31 of said copending application.

EXAMPLE 6 In a manner after Example 1, the following ingredients werereacted in a resin vessel in the proportions indicated: HET acid560parts; maleic anhydride95.6 parts; ethylene glyco17l.3 parts; diethyleneglycol-121.5 parts and tetrahydrofurfuryl alcohol4.6 parts. a Theforegoing ingredients were reacted until an acid number of 43.5 wasattained, whereupon the contents of the reaction vessel was cooled andthen cast under an inert atmosphere. The casting was a transparent,substantially colorless, hard, brittle unsaturated polyester, which whendissolved in 30 percent by weight of styrene and c0- polymerized,employing the benzoyl peroxide catalyst, gave a polyester resin having achlorine content of 30 percent, a result of 0.18 inch per minute to theASTM D-757-49 test, a color Hazen of 165, and a heat distortiontemperature of 82 degrees centigrade.

The following example illustrates the use of a chemical adduct ofhexachlorocyclopentadiene and fumaric acid in preparing compositions andcopolymers of this inven tion.

EXAMPLE 7 Six and two-tenths parts of ethylene glycol and 10.6 parts ofdiethylene glycol were charged in a resin vessel similar to thatdescribed in Example 1 then blanketed with an inert atmosphere, agitatedand heated to a temperature of about 100 degrees centigrade, whereupon38.9 parts of an adduct formed from fumaric acid and hexachlortcyclopentadiene, and 9.8 parts of maleic anhydride were added. Thereaction temperature was degrees centigrade, rising to degreescentigrade during the course of 20 hours. At the end of this period alight colored, clear, hard, brittle resin was obtained. On compounding100 parts of this resin with 30 parts of styrene and 0.03 part ofhydroquinone, a viscous solution was obtained which was catalyzed with 1percent of its weight of benzoyl peroxide, and cast. A hard, tough resinwas obtained, having a chlorine content of 26 percent by weight giving aresult of 22inch per minute to the ASTM D-757-49 test, a color l-lazenof 150, and a heat distortion temperature of 82 degrees centigrade.

The following Example 8 is similar to foregoing Examples 6 and 7 andrepresents a typical formulation of the polyester resins of thisinvention without any phosphorous containing compound present and is setforth to indicate a typical fire resistance result obtained from theforegoing described test ASTM D-757-49 in order to contrast this resultwith those obtained from testing compositions of Examples 9, 10, and ll,which have the same composition as that of Example 8 except thatphosphorus has been chemically combined in the polymerized resin bymeans of a cross-linking agent.

EXAMPLE 8 Into a suitable reaction vessel are charged 152 parts ofethylene glycol 11.6 parts of diethylene glycol, 388.8 parts of HETacid, 152 parts of adipic acid and 59.2 parts of furnaric acid. Theesterification was carried out at 160 degrees centigrade under an inertatmosphere of carbon dioxide until an acid number of 17.5 was reached.To 1600 parts of the unsaturated polymerizable resin was added 400 partsof styrene containing 0.14 part of hydroquinone inhibitor.Polymerization was carried out in a manner after Example 3. There wasobtained a clear, hard, resinous material having a 22.5 percent chlorinecontent by weight, a burning rate as set forth by the specifications ofASTM D75749 of 0.52 inch per minute.

EXAMPLES 9, 10, AND 11 Examples 9, l and 11 are similar to Example inthat phosphorus is introduced chemically into the copolyrnerized resinby means of a cross-linking agent. Table 1 following the examples showsthe effect on the burning rate of the materials of these examples asvarying amounts of phosphorus are added and also shows that the burningrate may be substantially improved by employing increasing amounts ofphosphorus even though the chlorine content of the resin at the sametime is decreased. The compositions of Examples 9, 10, and 11 were madeby adding bis (betachloroethyl) vinyl phosphonate in the varying amountsshown in Table I to portions of the styrenated resin of Example 8 butprior to its polymerization. To the clear resinous compositions obtainedin each case was added 1 percent by weight of a 50- 50 mixture ofbenzoyl peroxide and tricresyl phosphate. Polymerization was carried outin a manner after Example 3 resulting in each case in clear, hard,resinous materials. Example 8 is repeated in the table as a control.

A study of Table I reveals that by adding parts of his (betachloroethyl)vinyl phosphonate to 100 parts of the polyinerizable compositions ofthis invention and more particularly of Example 8, the fiarne resistancewas improved more than five fold, i.e., the burning rate became lessthan one-fifth the rate of the control material. Also the improvement inflame resistance was fairly proportional to the amount of the phosphoruscontaining material added, viz., the more of such material added, thegreater the improvement in fire resistance.

EXAMELE 12 Into a suitable reaction vessel were charged 91 parts ofethylene glycol, 22.2 parts of diethylene glycol, 388.87 parts of HETacid, and 78.8 parts of fumaric acid. The esterification was carried outat 160 degrees centigrade under an inert atmosphere of carbon dioxideuntil an acid number or" was reached. To 500 parts of the unsaturatedpolymerizable resin were added 200 parts of styrene containing 0.07 partof hydroquinone inhibitor. Polymerization was carried out in a mannerafter Example 3. There was obtained a clear, hard, resinous materialhaving a standard burning rate as set forth by the specification of ASTMD75749 of 0.19 inch per minute, a chlorine content of 28.9 percent byweight, a color Hazen of 120, and a heat distortion temperature of 92degrees centigrade.

1i? EXAMPLES 13, 14, 15, AND 16 T able II PHOSPHORUS DRIVED FROMCROSS-LINKING AGENT Chlorine content of final polymerized resin, percentHeat distortion temperature in degrees cent.

Polyester resinous composition and s tyrinc parts Di (chlorop w ExampleNo. propenyl Table II shows the effect on the heat distortiontemperature of the final copolymerized resins formed as the maximumamount of di (chloropropyl) propenyl phosphonate which can be chemicallyreacted with the poly ester portion of the resin is approached and thenexceeded. Further discussion of the impoitance of this data is had in alater portion of this application.

The following Examples 17 through 25 typify formulations in wihchphosphorus is introduced into the final copolymerized resin compositionor into the unpolymerized polyester resinous compositions by means ofintroducing a particular phosphorus containing compound into theesterification reaction vessel with the materials to be esterified. InExamples 17 and 18 the phosphorus is derived from a material whichreacts with the acid portion of the polyester. In Example 19 thephosphorus is derived from a material which reacts with both the acidand the alcohol portions of the polyester while in Examples 20 through25, the phosphorus is derived from a material which reacts with thealcohol portion of the polyester. The phosphorus compounds listed inthese examples are typical of those which may be used in practicing ourinvention but are not to be interpreted as being the only ones which canbe used. Typical results obtained when testing representative materialsof Examples 17 through 25 are set forth in Table III. This table alsorepeats as a control the results obtained when testing the material ofExample 12, the formulation of which is very similar to those ofExamples 17 to 25, except that it contains no phosphorus therein.

EXAMPLE l7 Into a suitable reaction vessel were charged 116.7 grams ofHET acid, 18.8 grams of tumaric acid, 24.3 grams of propylene glycol and15.0 grams of tris-methylol phosphine oxide. Esterification was carriedout at an elevated temperature of 160 degrees centigrade under an inertatmosphere of nitrogen until an acid number of 15.2 was reached. Toparts of the unsaturated polymerizable resin obtained were added 40parts of styrene containing .014 part of a hydroquinone inhibitor.Polymerization was carried out in a manner after Example 3 and a hard,clear, resinous material having the properties set forth in Table Illwas obtained.

EXAMPLE 18 Into a suitable reaction vessel were charged 4-27 parts ofethylene glycol, 112 parts of diethylene glycol, 111 parts of his(hydroxymethane) phosphinic acid, 1955 parts of HET acid and 396 partsof fumaric acid. The esterification ww carried out at degrees centigradeunder an inert atmosphere of nitrogen until an acid number of 38 wasreached. To 1000 parts of the unsaturated polymerizable resin obtainedwere added 400 parts of styrene containing 0.14 part of hydroquinoneinhibitor. Polymerization was carried out in a manner after Example 3and a clear, hard, resinous material having the properties set forth inTable 111 was obtained.

EXAMPLE 19 Three hundred and sixty-four parts of ethylene glycol, 89parts of diethylene glycol, 41.5 parts of hydroxymethyl phosphonic acid,314 parts of fumaric acid, and 1550 parts of HET acid were charged intoa suitable reaction vessel. The reactants were esterified under an inertatmosphere of nitrogen and at an elevated temperature of 160 degreescentrigrade until an acid number of 33.4 was reached. To 1000 parts ofthe polymerizable unsaturated polyester obtained were added 400 parts ofstyrene containing 0.14 part of hydroquinone inhibitor. Polymerizationwas carried out in a manner after Example 3 and a clear, hard, resinousmaterial having the properties set forth in Table III was obtained.

EXAMPLE 20 Nine hundred forty-three and three-tenths parts of ethyleneglycol, 230.8 parts of diethylene glycol, 34 parts of phosphorous acid,766.6 parts of fumaric acid and 4025.6 parts of BET acid were chargedinto a suitable reaction vessel. The reactants were esterified under aninert atmosphere of nitrogen and at an elevated temperature of 160degrees centigrade until an acid number of 33.5 was obtained. To 5000parts of the polymerizable unsaturated polyester obtained were added2000 parts of styrene containing 0.70 part of hydroquinone inhibitor.Polymerization was carried out in a manner after Example 3 and a clear,hard, resinous material having the properties set forth in Table III wasobtained.

EXAMPLE 21 Nine hundred forty-three and twenty-seven one-hundredthsparts of ethylene glycol, 230.75 parts of diethylene glycol, 56.87 partsof phosphorus trichloride, 766.57 parts fumaric acid and 4025.58 partsof HET acid were charged into a suitable reaction vessel. The reactantswere esterified under an inert atmosphere of nitrogen and at an elevatedtemperature of 160 degrees centigrade until an acid number of 32.3 wasobtained. To 5000 parts of the polymerizable unsaturated polyesterobtained were added 2000 parts of styrene containing 0.70 gram of ahydroquinone inhibitor. Polymerization was carried out in a manner afterExample 3 and a clear, hard, resinous material having the properties setforth in Table III was obtained.

EXAMPLE 22 Into a suitable reaction vessel were charged 236 parts ofethylene glycol, 58 parts of diethylene glycol, 11.2 parts of phosphoricacid (85%), 1006 parts of HET acid and 192 parts of fumaric acid. Theesterification was carried out at an elevated temperature of 160 degreescentigrade under an inert atmosphere of nitrogen until an acid number of34 was reached. To 1000 parts of the unsaturated polymerizable resinwere added 400 parts of styrene containing 0.14 part of hydroquinoneinhibitor. Polymerization was carried out in a manner after Example 3and a clear, hard, resinous material having the properties set forth inTable 111 was obtained.

EXAMPLE 23 Nine hundred fifty-nine and four-tenths of ethylene glycol,234.5 parts of diethylene glycol, 756 parts of fumaric acid, 198.3 partsof benzenephosphonic acid and 3851.8 parts of HET acid were charged intoa suitable reaction vessel. The reactants were esterified under an inertatmosphere of nitrogen and at an elevated temperature of 160 degreesCentigrade until an acid number of 28.2 was obtained. To 3000 parts ofthe polymerizable V EXAMPLE 24 Ninety-one parts of ethylene glycol, 23parts of diethylene glycol, 74 parts of fumaric acid, 47 parts ofphosphorus oxychloride and 389 parts of HET acid were charged into asuitable reaction vessel. The reactants were esterified under an inertatmosphere of nitrogen and at an elevated temperature of 160 degreescentigrade until an acid number of 36.1 was obtained. To parts of thepolymerizable unsaturated polyester were added 40 parts of styrenecontaining 0.014 part of hydroquinone inhibitor. Polymerization wascarried out in a manner after Example 3 and a clear, hard, resinousmaterial having the properties set forth in Table 111 was obtained.

EXAMPLE 25 parts of styrene containing .014 part of hydroquinoneinhibitor. Polymerization was carried out in a manner after Example 3and a clear, hard, resinous material having the properties set forth inTable III was obtained.

Table III PHOSPHOROUS DERIVED FROM POLYESTER PORTION 1 OF RESIN Chlorinecon- Phosphorous tent before content be- Burning Ex. Phosphorous ctg.and after fore and after rate in in. N0. cpd. styrenating styrenat'mgper min. as per ASTM 757-49 Before After Before After 12 40. 4 28. 90.19 17. Tris-methylol phosphiue oxide 40. 0 28.0 2.1 1. 5 18-Bis-hydroxymethane phosphinic ac' 39. 3 28.1 1.0 0. 72 l9 Hydroxymethylphosphonic acid 45. 8 32. 7 O. 54 0. 39 O 10 20- Phosphorous acid 40. 528. 9 0. 24 0.17 O 10 21- Phosphorous tric loride 40. 6 29.0 0. 24 0.170.12 22 Phosphoric acid 37.7 26. 9 0.21 O. 15 0. 12 23. Benzenephosphonie acid 39.0 27. 9 0.72 0.51 0. 12 24 Phosphorous oxychloride39. 6 28. 3 1.8 l. 3 25. Phosphorous pentaohloride 41. 9 29. 9 1. 7 1. 2

A study of Table III shows that the fire resistance of the resins ofthis invention may also be greatly improved when the chemically combinedphosphorus of the ffinal copolymerized resin is derived from thepolyester portion of the resin. For example the burning rate is justabout halved (0.19 to 0.10 inch per minute) when hydroxymethylphosphonic acid or phosphorous acid are used, while slightly lesssubstantial improvements are realized when using other of the phosphoruscontaining compounds shown.

The following examples set forth in Table IV indicate how variousproperties change as the proportion of styrene in the finalcopolymerized resins of this invention is changed. Type A resin issimilar to that of Example 12. These resinous compositions werestyrenated and polymerized as previously described.

Table IV Percent P be Styrene Percent Clbe- Viscosity Phosphorus ctg.fore and after in parts fore and after in poise Ex. N 0. Type cpd. addedto the styrenating per hun- Acid No. ASTM styrenating at 23 deresmesterification dred of D-757-49 grees reactants resin cent.

Before After Before After Phosphorous acid 0. 0. 14 35. 5 0. 1O 40 28. 625. 7 d 0.20 0. 13 35. 5 0.11 40 26. 6 7. 4 0.20 0.13 35. 5 0.10 40 25.80.20 0.12 35. 5 0.11 40 25.0 1. 3

The table shows that as styrene is added, prior to polymerization, theviscosity is reduced almost 20 times without incurring a loss in fireresistance. This is important because for many commercial processes, lowviscosity resinous compositions are necessary. The table also shows thateven though the chlorine content of the final copolymerized resins islowered by the increasing amounts of styrene added, the flame resistanceof the resins is not adversely aiiected. In contrast to this, the sametype resin A, without any phosphorus incorporated therein gives burningrates of 0.19, 0.21, 0.22, and 0.23 in Examples 26, 27, 28, and 29respectively.

The following polyester resinous compositions set forth in Table V aresimilar to these previously described and are also capable of havingtheir flame resistant properties improved by the addition of phosphorousby means of any of the phosphorus containing materials previouslymentioned:

Table V EXAliPLE 39 A resin was made using the following proportion ofmaterials: I-IET acid 633.1 parts, fumaric acid 128.1 parts, ethyleneglycol 143.3 parts, diethylene glycol 36.2 parts, triethyl phosphate60.0 parts. This mixture was Ex. Ethylene No.

glycol Diethylene glycol M aleic Adduet of hexahalocyclopentadiene anddienophile other than HEI auhydride or HET acid Adduct oihexahaloeyclopentadiene and tuniaric acid.

Cast material of Example 4 +diallyl 1,4,5,6,7,7-hexachlorobicyelo(2.2.1)-5-hcptene-2.3-dicarboxylate (adduot of hexaohlorocyclopenta-(liene and maleic auhydride diesteritied with allyl alcohol).

1,4,5,6,7,7-hexachloro-Z-methylbicycle-(2.2.1)5-heptene-2,3-dicarboxylic anhydride (adduet of hexahalccyclopentadiene and citraconicanhydride).

Mono-methyl ester oi1,4,5,6,7,7-

hex-achlorobicyc1s(2.2.1)-5-heptene- 2,3-(licarboxylic acid (adduet ofhexahalocyclopentadiene and maleic anhydride, half esterified withmethanol).

3-(1,4,5,6,7,7-hexachlorobicyclo-(2.2.1)-

5-hepte'ne-2-yD-methoxy-l,2- propanedic-l (sdduct ofhexahalocyclopentadiene and alpha allyl glycerol ether).

1,4,5,G-tetrachloro-7-7-difiuorohicyclo-(2.2.1)-5-heptene-2,3dicarboxylic acid (adduct 01 1,2,3,4-tetraehloro-5,fi-difluorocyclopentadiene and maleic anhydride).

1 ,4,5,6,7,7-hexachlorobicyclc-(2.2 .1) -5-heptene-Z-acetie-2-carboxylic anhydridc (adduet ofhexahalocyelopeutadiene and itaeonic anhydride)2,3dimethy1ol-1,4,5,6,7,7-hexochlorohicyclo (2.2.l)-5-heptene (adduct ofhexahalncyclopcntadienes and 2- ntene-Le-diol) 1 ,4,5,6,7 ,7-hexaehl0ro-2-chloro-bieyolc (2.2.1)-5 heptene-2,3-dicarboxylicanhydride (adduct of hexahaloeyclopentadiene and chlorornaleieanhydride) The following Examples 39 through 44 are given in order toestablish that when proceeding in accordance with our invention thephosphorus becomes chemically combined in the polymerized resin.Examples 39, 40, .41, and 42 show that when triethyl phosphate,tricresyl phosphate, triphenyl phosphate or tributyl phosphate areincorporated in the polyester resin by the procedures depicted thatthese are not chemically combined into the charged into a 1 literreaction vessel with nitrogen inlet leading to the bottom of the flask,stirrer, thermometer and means for distillation of water ofesterification. The mixture was heated with stirring and passage ofnitrogen through the mixture at a temperature of degrees centi grade,until an acid number of 32.5 had been reached. This mixture was pouredinto trays and 100 parts were then dissolved in 40 parts of styrene. Onehundred parts final polymerized resin but merely are physically com- 75of the styrenated solution of resin was mixed with two A resin was madeby reacting 633.1 parts of HET acid, 128.1 parts of fumaric acid, 148.3parts ethylene glycol and 36.2 parts diethylene glycol. These materialswere charged into a 1 liter reaction vessel provided with a nitrogeninlet, a stirrer, a thermometer and means for distillation of water ofesterification. The reaction was carried out at 160 degrees centigradewith stirring and nitrogen passing through the mix. When an acid numberof 34 had been reached the resin was poured out into a tray and allowedto cool. To 100 parts of this resin was added 40 parts of styrene andthe mixture was brought to complete solution. To 100 parts of thisstyrenated resin was then added parts of tricresyl phosphate. Thismixture was catalyzed by adding 2 parts of Luperco ATC, a mixture of 50parts of tricresyl phosphate and 50 parts of benzoyl peroxide. Thecatalyzed resin was poured into a tube and cured at 50 degreescentigrade in a water bath for 24 hours followed by 24 hours curing at120 degrees centigrade. The heat distortion was then determined and itwas found to be 83 degrees centigrade.

EXAMPLE 41 The styrenated resin composition of Example 40 was also usedin this example, 41. To 100 parts of this sty renated resinouscomposition was added 10 parts of triphenyl phosphate. The catalyzationand curing of this resin were carried out in the same manner as Example40. In this case the heat distortion temperature was found to be 83degrees centigrade. Triphenyl phosphate, and tricresyl phosphate arewell known in the art as being flame proofing additives for resins andplastics. It also is well known that they exhibit a plasticizing actionand that they lower the heat distortion temperature of the rigidthermoset products to which they are added.

EXAMPLE 42 Eight hundred three and four-tenths grams of HET acid, 162.6grams of fumaric acid, 169.6 grams of ethylene glycol, 46.0 grams ofdiethylene glycol and 39.9 grams of tributyl phosphate were charged intoa 1 liter reaction vessel provided with means for introduction ofnitrogen to the bottom of the reaction mix, a stirrer, thermometer andan outlet for distillation of water of esterification. The reactionvessel was heated with stirring and passage of nitrogen at a temperatureof 160 degrees centigrade until an acid number of 43 had been reached.The contents were then cast out into trays. One hundred parts of thisbase resin were dissolved in 40 parts of styrene. The Water ofesterification of this reaction was analyzed for butyl alcohol. It wasfound that 0.5 gram of butyl alcohol had been distilled out of thereaction Had complete esterification taken place with the tributylphosphate a total of 66.7 grams of butyl alcohol would have been presentin the distillate. The fact that the alcohol did not distill outindicates that very little or no reaction of the tributyl phosphate hadtaken place. One hundred grams of the styrenated resinous composition ofthis example was catalyzed with 2 parts of Luperco ATC, a mixture of 50parts tricresyl phosphate and 50 parts of benzoyl peroxide. Thiscatalyzed resin was cast into tubes and cured at 50 degrees centigradein a water bath for 24 hours followed by 24 hours curing at 120 degreesC. in an oven. A sample of this casting was tested for heat distortiontemperature which was found to be 39 degrees centigrade.

16 EXAMPLE 43 A resin was made using the following proportion ofmaterials: HET acid 633.1 parts, fumaric acid 128.1 parts, ethyleneglycol 162.6 parts, diethylene glycol 36.2 parts, phosphorous acid 189parts. This mixture was charged into a 1 liter reaction vessel withnitrogen inlet leading to the bottom of the flask, stirrer, thermometerand means for distillation of water of esterification. The mixture washeated with stirring and passage of nitrogen through the mixture at atemperature of 160 degrees centigrade, until an acid number of 32.5 hadbeen reached.

This mixture was poured into trays and parts werethen dissolved in 40parts of styrene. One hundred parts of the styrenated solution of resinwas mixed with 2 parts of Luperco ATC, a mixture of 50 parts oftricresyl phosphate and 50 parts benzoyl peroxide. This was cast into atube and heated in a water bath at 50 degrees centigrade for 24 hours,followed by 24- hours heating at 120 degrees centigrade. A sample ofthis casting was then cut into samples for heat distortiondetermination. The heat distortion temperature of this resin was degreesC.

EXAMPLE 44 A resin was made using the following properties of materials:HET acid 633.1 parts, fumaric acid 128.1 parts, ethylene glycol 148.3parts, and diethylene glycol 36.2 parts. The mixture was charged into a1 liter reaction vessel provided with nitrogen inlet leading to thebottom of the flask, stirrer, thermometer and means for water ofesterification distillation. The flask was heated at a temperature of160 degrees centigrade until an acid number of 34 had been reached. Themixture was then poured out into trays and allowed to cool. One hundredparts of this base resin was dissolved in 40 parts of styrene. Onehundred parts of the styrenated solution was mixed with 2 parts ofLuperco ATC, a mixture of 50 parts tricresyl phosphate and 50 partsbenzoyl peroxide. This catalyzed resin was cast into tubes and cured at50 degrees centigrade in a water bath for 24 hours, followed by curingat degrees centigrade for 24 hours. Heat distortion samples were cutfrom this casting. The heat distortion temperature of this resin was 105degrees C.

Not only are heat distortion temperature results impaired whennon-reactive phosphorus containing materials are added, even in smallamounts, but they are also impaired when phosphorus containing materialshaving limited ability to combine chemically into the resin are used inexcess of the amount that can be combined. Evidence of this is derivedfrom Table I pertaining to the results obtained in heat distortiontemperatures as the quantity of phosphorus added (derived from di(chloropropyl propanylphosphonate)) is changed. In those ex amples wherethe maximum limit of phosphorus in chemical combination has beenapproached, the heat distortion temperature results show an improvementover resins without any phosphorus incorporated therein or at least areapproximately as good as resins without any phosphorus incorporatedtherein, while in that example where the limit of phosphorus in chemicalcombination has been exceeded, the di (chloropropyl propenylphosphonate)then functions as a plasticizer and the heat distortion temperatureresult falls off badly.

The processing techniques and the chemical reactions depicted herein forproducing the necessary ingredients to be used in making thecompositions of this invention are subject to various modifications andthe proportions of ingredients may also be varied without departing fromour invention.

The temperature for carrying out the reaction between a the polyhydricalcohols and polybasic acids ranges from 100 degrees centigrade and to200 degrees centigrade, although higher or lower temperatures can beused; preferably around degrees centigrade to degrees centigrade isadvantageously employed.

An inert gas such as nitrogen is passed through the mixture in apreferred procedure to accelerate the progress of the reaction and allowfor good color of the product. The progress of the reaction is followedby measuring the rate of Water liberated, by the viscosity of the resin,by its acid number, or by other methods commonly known in the art. Theextent to which the reaction is carried out will depend on a number offactors, such as the desired viscosit melting point, duration ofreaction, etc.

Esterilication catalysts such as para-toluene sulfonic aci benzenesulfonic acid, beta naphthalene sulionic etc, or amines such as,pyridine, triethyl amine, quinoline, etc., may be added to the reactionmixture.

The proportion of polyhydric alcohol is approxirnately controlled by thetotal mol proportion of acids in the esterification reaction mixture. inmaking certain compositions of our invention we prefer to react thepolyhydric alcohols and polybaslc acids in a roughly equimolarproportion, however, e her the acids or mcohols may be in substantialexcess, if it is desired to form a low molecular weight polyester resin.

A chain stopper may be added in a minor proportion depending on themolecular weight of the linear unsaturated polyester chain desired, inorder to rapidly teriinate the growth of the unsaturated polyester chainduring the esterification reaction and when the desired acid her isbeing approached, or, to reduce the number of free carboxyl or hydroxylgroups, or, to introduce a hydrocarbon terminal residue. Among thecompounds which may be used as chain stoppers during the esterificationreaction whereby the unsaturated polyester chain is produced are a widevariety of monohydric alcohols, such as, but l, hexyl, octyl, dodecyl,beuzyl, tetrahydrofurturyl, etc. or, monobasic acids, such as, acetic,propionic, butyric, ethyl hexoic, benzoic, etc.

The solution or mixture of unsaturated polyester olefinic cross-linkingagent is preferably made while the unsaturated polyester is still hot,thereby facilitating rapid solution. Alternatively, the unsaturatedpolyester may be cooled and stored and when ready for mixing may beheated in order to facilitate solution in the olefin, which may also beheated. The solution may, of course, be made in the cold, especially ifthere is any possibility of explosion in handling the hot olefiniccross-linking agent or if polymerization of the olefinic cross-linkingagent cannot be prevented when at elevated temperatures even by thepresence of inhibitors therefor.

The proportion of olelinic cross-linking agent to unsaturated polyestermay be varied within the ultimate limits of each without departing fromthe scope of this invention, in order to make the solution or mixture ofthis invention which may be set to th infusible, insoluble, polyesterresin. For example, only a small proportion of olefinic cross-linkingagent is needed when the proportion of reactive cr ss-li liable olefinicbonds in the unsaturated polyester is very small; and a still smallerproportion of olefinic cross-linking agent may be employed if it isdesired to react only a part of the total of said unsaturated bonds insuch polyester in the cross-linking reaction. On the other hand, a majorproportion of olefinic cross-linking agent to unsaturated polyester beemployed the proportion of reactive cross-linkable oleiinic bonds in theunsaturated polyester is high; and a still higher proportion of olefiniccross-linking agent will be required if it is desired to react a majorpart of the total of said unsaturated bonds in such polyester in thecross-linking reaction. In general, the concentration of the unsaturatedpolyester in the olefinic cross-linking agent may vary between about and90 percent. In certain formulations and in order to accentuate a largenumber of desirable properties in the polyester resin produced, we findit preferable to employ between about and percent of the olefiniccross-linking agent, e.g., styrene, when the unsaturated polyester issimilar to that produced in Example l8 1; however, it is to beunderstood that this preferred concentration is a variable which isdictated by the particular properties of the materials employed and theparticular properties desired in the polyester resin produced.

Polymerization inhibitors, usually of the order of 0.001 to l percent ofthe composition may be added to prevent premature polymerization. Amongthe inhibitors which may advantageously be employed to prevent thepremature polymerization of the mixture of unsaturatedpolyester andolefinic cross-linking agents, particularly if the mixture is to bestored or shipped in commerce prior to curing, are substances such ashydroquinone, berzoquinone, para-tertiary-butyl catechol, paraphenylenediamine, trinitroberlene, picric acid, etc.

Polymerization catalysts are preierably added to the mixture ofunsaturated polyester and olefinic cross-linking agent to effect settingor curing. Catalysts such as benzoyl peroxide, acetyl peroxide, lauroylperoxide, methyl ethyl lzetone peroxide, cuinene hydroperoxide, etc.,have been found satisfactory. Such catalysts are used in a proportion of9.01 to 10 percent depending on the elliciency of their action andwhether or not substances which in ibit polymerization are present inthe mixture to be cross-linked. The polymerization reaction may also behastened by efiecting it in the presence of promoters such as metals ormetal salts, cobalt maleate, cobalt naphthenate, etc., or, by aminessuch as dibutyl amines, or mercaptans such as dodecyl lnercaptan, etc.These are used in proportions similar or smaller to that stated forcatalysts.

The polymerization conditions for effecting the cross linking reactionbetween the unsaturated polyesters of this invention and tne olefiniccross-lin ing agent may be sel cted from a wide variety of techniquesbut usually involve the application of heat or light. Although pressureis not a required condtion for effecting polymerization of thepolymerizable mixtures embraced within this invention, thereby providinga decided advantage over other insoluble, iniusible resins knownheretofore, it is someirnes advantageously employed, particularly whenit is cesired to madte laminates in preformed shape. The presures foundsatisfactory for this purpose are relatively low compared to thoserequired for molding or laminating other type resins than involvedherein and may be of the order of that obtained by pressing glass plateshaving a fiber glass mat or laminate impregnated with the polyesterresin sandwiched therebetween.

The temperature at which polymerization is efiected depends on a varietyof factors, particularly the boiling point or" the olefiniccross-linking agent and the exothermic characteristics of thepolymerization mixture. A temperature is selected which will give asuitable reaction rate and yet not cause substantial volatilization, andin the case of producing very tlr'ck castings, which will not produce aproduct which is crazed, cracked, etc.

Various hexahalocyclopentadienes may be employed in making compositionsembraced within the scope of this invention such as the chloro, bnomoand fluoro' substituted cyclopentadienes wherein all of the hydr'ogensare replaced by one or more of the foregoing halogens. Whilehexachlorocyclopentadiene is today the most readily availablehexahalocyelopentadiene, we have found that the mixed perhalo compoundsare useful in making Diels- Alder adducts which can be chemicallycombined into the saturated polyester compositions of this invention.

in fact, hexachlorocyclopentadiene in which one or two of the chlorineatoms has been replaced with bromine, appears to afiord an even higherdegree of flame retardance in the polyester resins. The polyester resinsmade from a hexahalocyclopentad-iene in which some of the chlorine ofhexachlorocyclopentadiene has been replaced with fluorine atoms, areexceedingly interesting materials possessing eii'nanced heat resistanceand aging properties. The foregoing applies whether thehexahalocyclopentadiene is 19 utilized as a raw material in the makingof the copolymerizable linear polyester or the unsaturated cross-linkingagent.

The compounds useful in making adducts of hexahalocyclopentadienes aredienophiles having a plurality of esterifiable groups. These functionalgroups capable of esterification and having utility herein are found incompounds such as substituted or unsubstituted acids, anhydrides, acidhalides, alcohols and esters, m hereinbefore illustrated.

The hexahalocyclopentadiene radical may be combined into thepolycarboxylic acid unit of the unsaturated polyester chain in a varietyof ways such as by effecting the Diels-Alder reaction of thehexahalocyclopentadiene with unsaturated polycarboxylic acids such asmaleic or fumar-ic; substituted maleics or fumarics such as, citraconic,chloromaleic, mesaconic, and py'rocinchonic; acetylene dicarboxylicacids; and also ethylenic substituted succinic anhydrides or acids, suchas, aconitic and itaconic, etc. Instead of employing the polycarboxylicacids or anhydrides in the Diels-Alder reaction, adducts ofhexahalocyclopentadiene with substances which produce an equivalentpolyester chain upon reaction with a polyhydric alcohol can be used; forinstance, acid chlorides, or, esters of the acids or anhydrides may alsobe used. A typical illustration is had in the Dials-Alder reaction or"hexachlorocyclopentadienewith fumaryl chloride to produce 1,4,5,6,7,7hexachlorobicyclo- (2.2.1)--heptene-2,3-dicarbonyl chloride followed bythe esterification or this with ethylene glycol and maleic anhydride toproduce the unsaturated polyester. In place of the acid chloride,diesters such as, dimethyl maleate may be employed.

The hexahalocyclopentadiene radical may be combined into the polyhydricalcohol unit of the unsatured polyester chain in a variety of ways suchas, by effecting the Diele- Alder reaction of thehexahalocyclopentadiene with unsaturated polyhydric alcohols such as,butene-diol or pentene-diol, etc. Other suitable compounds are others oresters derived from polyhydric alcohols having at least three hydroxylgroups, one of which is ester-ified or etherified with an unsaturatedalcohol or acid reactive with hexahalocyclopentadiene in the dienesynthesis. For instance, allyl or vinyl glycerol ethers, allyl or vinylpentaerythritol ethers; and unsaturated acid esters of glycerol orpentaerythritol, etc., such as, acrylic or methacrylic esters thereofmay be used. Instead of employing a polyhydric alcohol in theDiels-Alder reaction, adducts of hexahalocyclopentadienes withsubstances which produce an equivalent unsaturated polyester chain, uponreaction with a polycarboxylic acid can be used; for instance, esters ofthe alcohols may also be used.

The unsaturated polyester chains produced by efiecting the Diels-Alderreaction of hexahalocyclopentadiene with an unsaturated polycarboxylicacid or polyhydric alcohol, followed by the esterification of theproduct so produced with a polyfunctional alcohol or acid, can berendered copolymerizable by chemically combining in such polyesterchains, a reactive and unsaturated chemical ingredient which retains itsactive unsaturation after its chemical combination into the polyesterchain. Among the materials which may gainfully be employed for thispurpose are the unsaturated polycarboxylic acids such as, maleic,fuman'c, citraconic, itaconic, acetylene dicarboxylic and esters andhalogen substituted derivatives thereof, etc.; the unsaturatedpolyhydric alcohols such as, butene-diol, pentene-diol, etc., alsounsaturated hydroXy ethers such as allyl or vinyl glycerol ethers, allylor vinyl pentaerythritol ethers, etc.; and, still other chemicalcompounds comprising an ethylenic or an acetylenic linkage which are notrendered unreactive in the polyester chain by their chemical combinationinto the polyester chain by way of other functional groups, whereby themixed esters are produced.

Another method of providing for copolymerizable unsatuation in thepolyester chain which may be employed involves: effecting the dienesynthesis of hexachlorocyclopentadiene with a polybasic alcohol or acidor ester, or equivalents thereof, which contains at least two olefiniclinkages, one of which is reactive in the diene synthesis, while theothers which are unreacted, are capable of being copolymerizable in thecross-linking reaction. Among the materials which are useful for thispurpose are acetylenic compounds and di-olefinic and poly-olefiniccompounds.

Alternatively, or in addition to including the flame retardant componentin the unsaturated polyester, we have found that the chlorine content ofthe final polyester formulations may be obtained, or substantiallyincreased, by employing a cross-linking agent which also contains thecomponent which imparts flame retardance to the final compositions ofthis invention. Among such cross-linking agents which may be useful forthis purpose are the following: Diallyl1,4,5,6,7,7-hexachlorobicyclo-(2.2.l)-5- heptene-Z,3-dicarboxylate;diallyl l,4,5,6,7,7-hexachloro- Z-methylbicyclo (2.2.1)S-heptene-Z,3-dicarboxylate; di

allyl l,2,4,5,6,7,7heptachlorobicyclo-(2.2.1)-5-heptens-2,3-dicarboxylate; andtriallyl-1,4,5,6,7,7-hexachlorobicyclo (2.2.l)-5-heptene-2-acetate-2,3-dicarboxylate. These compounds can be prepared byreacting hexachloro cyclopentadiene with the indicated dicarboxylic acidand ester ifying the resultant product with an unsaturated alcohol suchas allyl alcohol. Other cross-linking agents may advantageously beemployed; for example, reaction products of henachlorocyclopentadienewith isoprene or butadiene retaining a reactive unsaturated linkage canbe used as cross-linking agents directly without further reaction. Stillother methods for the preparation of the unsaturated cross-linkingagents, employing type reactions known to the art, will be apparent fromthe foregoing. In addition materials such as triallyl cyanurate may beemployed for improving heat resistance; divinyl benezne,monochlorostyrene, dichlorostyrene, diallyl phthalate, diallyl maleateand similar monoor poly-vinyl or monoor poly-allyl derivatives are alsouseful.

t is apparent from a consideration of the foregoing examples and theforegoing discussion that the particular chemical ingredients selectedand their relative proportions may be varied over a wide range toproduce a wide variety of compositions embraced within this invention.It should be emphasized that modifications can be made to accentuate anygiven property or cornbina-tion of properties desired. For example,hardness in the final po-iyester resin can be varied by using a shortchain polyhydric alcohol and acids or long chain polyhydric alcohols andacids; the viscosity of the mixture comprising the unsaturated polyesterand olefinic cross-linking agent may be varied by changing the ratio ofunsaturated polyester to olefinic cross-linking agent; and the curingcharacteristics of such mixtures can be varied by changing the kind andproportion of polymerization catalyst employed. In order to accentuateboth flame retardance and heat resistance, we prefer that thehexachlorocyclopentadiene content should not comprise less than sevenpercent by weight of the polyester resin compositions; the upper limitfor the hexachlorocyclopentadiene content is generally dictated bypractical limits determined by the minimum necessary concentration ofglycols and unsaturated dibasic acids not being adducts ofhexachlorocyolopentadiene and olefins to give resinous compounds capableof being hardened and this upper limit is about 60 percent. Flameretardance may be accentuated by adding to the unsaturated polyestercontaining the hexachlorocyclopentadiene component, a cross-lirdc'ngagent which also contains the flame retardant component made fromhexachlorocyclopentadiene in chemical combination therewith. It may befurther accentuated by esterifying a polycarboxylic acid and polyhydricalcohol which each contain the hexahalocycloentadiene flame retardantcomponent of this invention and cross-linking this with a fire resistantcross-linking agent. It may be even further accentuated by chemically 21incorporating phosphorus in the in this application.

The properties of the compositions of this invention can be variedsubstantially by incorporating modifying agents before, during or afterany of the processing steps employed. For example, instead of producingarticles of commerce trom the compositions of this invention which arein the form of castings or laminates as previously described herein, afoamed type article may be made by incorporating a small percentage of afoam ring agent such as sodium bicarbonate into the solution ofunsaturated polyester dissolved in mono-olefin and thereafter efiectingthe copolymerization in the presence of catalyst and heat to produce thefoamed article. Formuiations which are useful for making moldingsembodying the compositions of this invention may be made by mixing intothe unsaturated linear polyester and olefinic crossdinking agentmixture, an inert filler such as chopped fiber glass rivings, maceratedfabric, asbestos fibers, mica, etc, which serve a fibrous reinforcingmedia and incorporating a small percentage of a mold lubricant, catalystand/ or promoter.

An infinite variety of products may also be prepared, which embody thecompositions of this invention, by 160' polymerizing the linearunsaturated polyester materials produced in accordance with invention,as in Example 1, with a mono-olefinic cross-linking agent in thepresence of another copolymerizable linear polyester material havingdifferent structure than that produced by this invention. For example,by dissolving 23. 1 parts of the product of Example 1 and 4.3 parts ofan unchlorinated commercial polyester resin dissolved in styreneespecially designed for imparting flexibility and designated as Parafiexl13 (made by Rohm & Haas Company, Philadelphia, Pennsylvania) and 2.3parts by weight of styrene and effecting the copolymerization of themLxture by a catalyst a material produced which has better fiexioilityand different properties than any materials produced heretofore. It isto be understood that dyes, pigments, plasticizers, lubricants andvan'ious other modifying agents are contempiated as being hicorporatedin certain formulations to produce compositions embraced in thisinvention in order to obtain or accentuate any given property.

This application is a continuation-in-p t of our oopend'mg application,Serial No. 308,921, filed Sept. 19, 1952, now United States Patent2,779,701.

Having thus described our invention what we claim and desire to secureby Letters Patent is:

1. A polymerizable mixture comprising (A) a polymerizable linearpolyester resin, comprised of the reaction product of a polycarboxylicacid and a polyhydric alcohol, said resin having olefinic polymerizableunsaturation and (B) a vinylidene monomer; an ingredient (I) ofsaidmixture containing a chemically combined component which is achemical reaction adduct of hexahalocyclopentadiene wherein the halogenis selected from the group consisting of chlorine, bromine, fluorine,and mixtures thereof, with a material selected from the group consistingof a polyearboxylic compound containing aliphatic carbon to carbonunsaturation and a polyhydric alcohol containing aliphatic carbon tocarbon unsaturation, wherein said polycarboxylic compound is selectedfrom the group consist ng of polycarboxylic acids, polycarboxylic'anhydrides and polycarboxylic acid halides,

ways previously described and an ingredient (II) of said mixturecontaining a compound of phosphorus, both the addruct of I and thephosphorus of II being chemically combined in the polymerized resin whensaid polymerizable mixture is copolymerized, and wherein said compoundof phosphorus is combined in saidvrinylidene monomer, and is selectedfrom the group consisting of his (betachloroethyl) vinyl phosphonate anddi (chloropropyl) prope-nyl phospho-nate bis (betachioroethynvhiylphosphonate.

2. A polymerizable mixture according to claim 1 wherein the compound ofphosphorus is bis(betachloroethyl) vinyl phosphonate.

3. A polymerizable mixture according to claim 1 whereinthe compound ofphosphorus is di(chloropropyl) propenyl phosphonate.

4. A composition of claim 1 wherein the ingredient (i) contained in the(A) portion of the polymerizable mixture.

5. A composition of claim 1 wherein the hexahalocyolopentadiene ishexachlorocy-clopentadiene.

6. A composition of claim 1 when polymerize-d to an infusible,insoluble, resinous composition.

7. A composition of claim 1 when mixed with an inert filler andpolymerized to on infusible, insoluble, resinous composition.

8. A reinforced plastic article comprising a composition of claim 1 whenpolymerized to an infusible, insoluble, resinous composition, and afibrous reinforcing medium.

9. A laminated article comprising a plurality of sheets of glass fibrousmaterial and as a binder therefor, an infusible, insoluble, resinouscomposition resulting from the polymerization of a composition definedin claim 1.

'10. A composition of claim 1 when having at least 7 percent by Weightof halogen content of the total mixture and wherein the chemicallycombined phosphorus is present in an amount between 0 .05 percent and 10percent by Weight of the total mixture.

'11. A composition of claim 4 wherein the ingredient (-1) is containedin the acid portion of (A).

12. A composition of claim 4 wherein the ingredient (I) is contained inthe alcohol portion of (A).

13. A composition of claim 11 wherein said adduct is the chemicalreaction adduct of hexahalocyclopentadiene and a polycarboxyl-iccompound containing aliphatic carbon to carbon unsaturation selectedfrom the group consisting of polycarboxylic acids, polycmboxylicanhydrides, and polycarboxylic acid halides, wherein the halogen isselected from the group consisting of chlorine, bromine, fluorine, andmixtures thereof.

14. A composition of claim 12 wherein said adduct is the chemicalreaction adduct 02f hexahalocyclopentadiene and a poly-hydric alcoholcontaining aliphatic carbon to carbon unsaturation wherein the halogenis selected from the group consisting of chlorine, bromine, fluorine,and mixtures thereof.

References Cited in the file of this patent UNITED STATES PATENTS2,586,885 Toy et al Feb. 26, 1952 2,639,252 Simon et a1 May 19, 19532,779,700 Robitschek et a1. Jan. 29, 1957 2,779,701 Robitschek Bit -a l.Ian. 29, 1957 2,863,794 Robitschek et a1 Dec. 9, 1958 2,863,795Robitschek et a1 Dec. 9, 1958

1. A POLYMERIZABLE MIXTURE COMPRISING (A) A POLYMERIZABLE LINEARPOLYESTER RESIN, COMPRISED OF THE REACTION PRODUCT OF A POLYCARBOXYLICACID AND A POLYHYDRIC ALCOHOL, SAID RESIN HAVING OLEFINIC POLYMERIZABLEUNSATURATION AND (B) A VINYLIDENE MONOMER; AN INGREDIENT (I) OF SAIDMIXTURE CONTAINING A CHEMICALLY COMBINED COMPONENT WHICH IS A CHEMICALREACTION ADDUCT OF HEXAHALOCYCLOPENTADIENE WHEREIN THE HALOGEN ISSELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE, FLUORINE, ANDMIXTURES THEREOF, WITH A MATERIAL SELECTED FROM THE GROUP CONSISTING OFA POLYCARBOXYLIC COMPOUND CONTAINING ALIPHATIC CARBON TO CARBONUNSATURATION AND A POLYHYDRIC ALCOHOL CONTAINING ALIPHATIC CARBON TOCARBON UNSATURATION, WHEREIN SAID POLYCARBOXYLIC COMPOUND IS SELECTEDFROM THE GROUP CONSISTING OF POLYCARBOXYLIC ACIDS, POLYCARBOXYLICANHYDRIEDES AND POLYCARBOXYLIC ACID HALIDES, AND AN INGREDIENT (II) OFSAID MIXTURE CONTAINING A COMPOUND OF PHOSPHORUS, BOTH THE ADDUCT OF IAND THE PHOSPHORUS OF II BEING CHEMICALLY COMBINED IN THE POLYMERIZEDRESIN WHEN SAID POLYMERIZABLE MIXTURE IS COPOLYMERIZED, AND WHEREIN SAIDCOMPOUND OF PHOSPHORUS IS COMBINED IN SAID VINYLIDENE MONOMER, AND ISSELECTED FROM THE GROUP CONSISTING OF BIS (BETACHOROETHYL) VINYLPHOSPHONATE AND DI (CHLOROPROPYL) PROPENYL PHOSPHONATE BIS(BETACHLOROETHYL) VINYL PHOSPHONATE.